From 7bafc99f200064b4efec56cc6112c23feff59f40 Mon Sep 17 00:00:00 2001
From: Eelco Dolstra <edolstra@gmail.com>
Date: Wed, 11 Jun 2025 16:34:36 +0200
Subject: [PATCH] Run nixpkgsLibTests in lazy trees mode

---
 packaging/hydra.nix | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/packaging/hydra.nix b/packaging/hydra.nix
index 664ee18ca..6df878239 100644
--- a/packaging/hydra.nix
+++ b/packaging/hydra.nix
@@ -187,6 +187,19 @@ in
           pkgs = nixpkgsFor.${system}.native;
         }
       );
+
+      nixpkgsLibTestsLazy = forAllSystems (
+        system:
+        lib.overrideDerivation
+          (import (nixpkgs + "/lib/tests/test-with-nix.nix") {
+            lib = nixpkgsFor.${system}.native.lib;
+            nix = self.packages.${system}.nix-cli;
+            pkgs = nixpkgsFor.${system}.native;
+          })
+          (_: {
+            "NIX_CONFIG" = "lazy-trees = true";
+          })
+      );
     };
 
   metrics.nixpkgs = import "${nixpkgs-regression}/pkgs/top-level/metrics.nix" {